Indications, applications, and outcomes of inferior vena cava filters for venous thromboembolism in Japanese patients.

A recent multicenter registry study of venous thromboembolism (VTE) patients in Japan demonstrated a high prevalence of inferior vena cava (IVC) filter placement. However, data regarding indications, applications, and outcomes of IVC filters in Japanese patients are quite limited. This study was an observational, single-center, retrospective cohort study of all consecutive patients with acute VTE treated between March 2006 and February 2014. Data extracted included patient demographics, indications, applications, and complications of IVC filters, as well as VTE recurrence and death. A total of 257 consecutive patients were analyzed. Seventy-eight patients (30 %) received IVC filters. The proportions of IVC filter placement were 26 % for deep-vein thrombosis (DVT) alone, 10 % for pulmonary embolism (PE) alone, and 46 % for both DVT and PE. There was no significant difference in patient demographics between the IVC filter group and no-IVC filter group. Stated indications for filter placement were 24 cases (30 %) of DVT in intrapelvic veins, 16 cases (20 %) of DVT in proximal veins, and 11 cases (14 %) of contraindication to anticoagulant therapy. In the IVC filter group, cases of class I indication (guidelines: JCS 75:1258-1281, 2009) numbered only 6 (8 %). Many of the retrievable IVC filters were not removed and placed permanently and the retrieval rate was 42 %. We found complications of IVC filters in 8 cases (10 %). IVC filter placement was significantly associated with a better survival rate and a higher incidence of DVT recurrence during a mean observation period of 541 days. Our research suggests the frequent use of IVC filters for VTE treatment, combined with a low retrieval rate. Most of the stated indications of IVC filter placement for VTE in Japanese patients were cases of DVT in intrapelvic veins or proximal veins, not cases of contraindication to anticoagulant therapy.